Eur. Phys. J. D (2015) 69: 256
https://doi.org/10.1140/epjd/e2015-60254-9

Regular Article

Effect of self-fields on the electron cyclotron maser instability in a dielectric loaded waveguide

¹ Physics Faculty, Kharazmi University, 49 Mofateh Ave, 15614 Tehran, Iran
² The Plasma Physics and Fusion Research School, Tehran, Iran
³ Department of Physics, Amirkabir University of Technology, P.O. Box 15875 -4413, Tehran, Iran

^a e-mail: el84111005@aut.ac.ir

Received: 26 April 2015
Received in final form: 9 September 2015
Published online: 17 November 2015

Abstract

The influence of self-fields on the cyclotron maser instability in a hollow electron beam propagating parallel to a uniform axial magnetic field B₀ê_z in a dielectric loaded waveguide is investigated. The theoretical analysis is carried out within the framework of linearized Vlasov-Maxwell equations. It is assumed that the beam is thin with the radial thickness much smaller than the beam radius. A new dispersion relation for azimuthally symmetric electromagnetic perturbation is derived and analyzed numerically. The influence of self-fields on the cyclotron maser instability in a dielectric loaded waveguide for different dielectric medium is studied. It is found that unlike the hollow waveguide the growth rate is increased by increasing self-fields. The instability band width decreases due to the increasing self-fields. The maximum growth rate increases gradually as self-fields increase as regards a different dielectric medium.